But the Barnet schoolgirl was reunited with them on Sunday (December 30), after she walked into Edmonton Police Station.

"We are delighted," step-dad Philip told MyLondon. "We couldn't believe the news that she was home.

"We are overwhelmed. So many people searched for her, from the press to friends. It's amazing."

Andrea went to Aylward Academy, in Edmonton, on Friday, December 21 and left her house in North Finchley at 7.30am. She was supposed to be home by 1pm that day but it got to 4pm and her family saw she had left her mobile phone at home.

Andrea was reported missing to the police, who along with worried family members and friends, started searching for the teenager. Philip says around 3,000 leaflets were handed out or stuck on walls around Barnet.

Andrea handed her self into Edmonton police station on Sunday, December 30 (Image: Missing People)

Philip fears that Andrea was taken in by a so-called “county lines” gang. Such gangs can use young and vulnerable people to deal drugs in parts of the country away from their homes.

"The police threw many resources at the search," Philip said. "Around 12 officers came to our house on Sunday and they were doing everything they could to look for her.

"Later that day, whoever was keeping her must have seen the police and publicity and let her go. She turned herself in to Edmonton Police Station.

"She walked through the door and said 'I am a missing person'. The police then contacted us and we rushed down there as soon as we could."

Andrea was missing for nine days in total, and is still in a state of shock, Philip says.

Her family are still unclear about what exactly she experienced while she was missing. They hope, if they give Andrea time, she will speak to them, as well as the police, about her ordeal.

"We have started speaking to her but last night (Sunday) wasn't really the right time to do that. There were other things we spoke to her about," said Philip.

"We don't know really what happened as she hasn't said. I am sure she will tell us and the police in good time but what we found on her phone before [she went missing] indicates people took her.

"Police are still treating it as though she was possibly taken by a gang. Everything indicates that she was groomed but thank God she is now home and alive."